#include <cstdio>
#include <iostream>
using namespace std;

int main() 
{
	freopen("fraction.in", "r", stdin);
	freopen("fraction.out", "w", stdout);
	long long a = 0, b = 0, c = 0, d = 0;
	cin >> a >> b >> c >> d;
	
	long long m = a * d + b * c;
	long long n = b * d;
	
	long long x = m;
	long long y = n;
	
	long long r = m % n;
	while ( r != 0 ) {
		m = n;
		n = r;
		r = m % n;
	}
	x = x / n;
	y = y / n;
	if ( y  == 1 ) {
		cout << x;
	}
	else {
		cout << x << "/" << y;	
	}
	fclose(stdin);
	fclose(stdout);
	return 0;
}
